Stripe rust (Puccinia striiformis f. sp. tritici) is one of the major devastating disease which causes large reduction in wheat yield. T. monococcum is an attractive diploid species for gene discovery in wheat with smaller genome size of 5700 Mb compared to 17,300 Mb of bread wheat. An adult plant stripe rust resistance QTL QYrtm.pau-2A was mapped on chromosome 2A flanked by two SSR markers Xwmc170 and Xwmc407. In the present study, two gene based markers Pau_Ta2AL_Gene45 and Pau_Ta2AL_Gene54 developed from 2A specific ESTs were found to map close to QYrtmpau-2A to narrow down the region for candidate gene identification. Utilizing sequence information of these two markers, four BAC clones were identified from the Minimum Tiling Path of 2AL assembly and were sequenced. SSR markers were designed from these BAC sequences and mapped to chromosome 2A. A 50 Mb region of wheat chromomse 2A was identified to harbor stripe rust resistance gene of T. monococcum. Gene based markers identified in the present investigation can be used for marker assisted introgression of QYrtm.pau-2A from T. monococcum to cultivated wheat. 相似文献
Natural plant populations encounter strong pathogen pressure and defence-associated genes are known to be under selection dependent on the pressure by the pathogens. Here, we use populations of the wild tomato Solanum chilense to investigate natural resistance against Cladosporium fulvum, a well-known ascomycete pathogen of domesticated tomatoes. Host populations used are from distinct geographical origins and share a defined evolutionary history. We show that distinct populations of S. chilense differ in resistance against the pathogen. Screening for major resistance gene-mediated pathogen recognition throughout the whole species showed clear geographical differences between populations and complete loss of pathogen recognition in the south of the species range. In addition, we observed high complexity in a homologues of Cladosporium resistance (Hcr) locus, underlying the recognition of C. fulvum, in central and northern populations. Our findings show that major gene-mediated recognition specificity is diverse in a natural plant-pathosystem. We place major gene resistance in a geographical context that also defined the evolutionary history of that species. Data suggest that the underlying loci are more complex than previously anticipated, with small-scale gene recombination being possibly responsible for maintaining balanced polymorphisms in the populations that experience pathogen pressure. 相似文献
Genome wide association studies allowed prediction of 17 candidate genes for association with nitrogen use efficiency. Novel information obtained may provide better understanding of genomic controls underlying germplasm variations for this trait in Indian mustard.
Abstract
Nitrogen use efficiency (NUE) of Indian mustard (Brassica juncea (L.) Czern & Coss.) is low and most breeding efforts to combine NUE with crop performance have not succeeded. Underlying genetics also remain unexplored. We tested 92 SNP-genotyped inbred lines for yield component traits, N uptake efficiency (NUPEFF), nitrogen utilization efficiency (NUTEFF), nitrogen harvest index (NHI) and NUE for two years at two nitrogen doses (No without added N and N100 added @100 kg/ha). Genotypes IC-2489-88, M-633, MCP-632, HUJM 1080, GR-325 and DJ-65 recorded high NUE at low N. These also showed improved crop performance under high N. One determinate mustard genotype DJ-113 DT-3 revealed maximum NUTEFF. Genome wide association studies (GWAS) facilitated recognition of 17 quantitative trait loci (QTLs). Environment specificity was high. B-genome chromosomes (B02, B03, B05, B07 and B08) harbored many useful loci. We also used regional association mapping (RAM) to supplement results from GWAS. Annotation of the genomic regions around peak SNPs helped to predict several gene candidates for root architecture, N uptake, assimilation and remobilization. CAT9 (At1g05940) was consistently envisaged for both NUE and NUPEFF. Major N transporter genes, NRT1.8 and NRT3.1 were predicted for explaining variation for NUTEFF and NUPEFF, respectively. Most significant amino acid transporter gene, AAP1 appeared associated with NUE under limited N conditions. All these candidates were predicted in the regions of high linkage disequilibrium. Sequence information of the predicted candidate genes will permit development of molecular markers to aid breeding for high NUE.
Molecular Biology Reports - Stripe rust and leaf rust are among the most devastating diseases of wheat, limiting its production globally. Wheat wild relatives harbour genetic diversity for new... 相似文献
Molecular and Cellular Biochemistry - Latest strategies for cancer treatment primarily focus on the use of chemosensitizers to enhance therapeutic outcome. N-3 PUFAs have emerged as the strongest... 相似文献
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Environmental heterogeneity affects distributions of plant species, although the effects of fine-scale heterogeneity on plant demographies are not widely studied. Diminutive winter annuals, especially rare taxa, can be sensitive to spatial variation in microenvironment as a consequence of their small stature above and belowground. To address whether spatial environmental heterogeneity affects demography, germination and fitness of Chorizanthe orcuttiana, an endangered winter annual distributed in distinct easterly and westerly microhabitats within an exceedingly narrow niche in California, we performed multiyear observational and empirical studies. We manipulated after-ripening environment, soil moisture and ambient light at both aspects, and profiled microclimate, soil physicochemistry and soil microbiomes at all sites. We show that easterly aspects host larger plants in larger populations, and have lower air temperatures combined with higher soil moisture in comparison to the west-facing sites. Yet, soil physicochemistry and microbiomes were similar across all sites. Manipulations of after-ripening conditions showed that seeds exposed to low humidity (17%) during dormancy and sown at easterly aspects exhibited the highest germination percentages, whereas seeds incubated in situ and subsequently sown at westerly aspects yielded the lowest germination. Simultaneous manipulations of soil moisture and light showed that at both aspects higher moisture combined with shade led to higher germination, whereas ambient soil moisture combined with shade yielded the lowest germination. Altogether, our studies show that the diminutive, rare winter annual C. orcuttiana exhibits higher germination and plant fitness under cooler soil conditions with higher soil moisture while preferring drier environments during after-ripening. 相似文献
Antonie van Leeuwenhoek - We report three yellow-pigmented, Gram-negative, aerobic, rod-shaped, motile bacterial isolates designated as PPL1T, PPL2, and PPL3 from healthy basmati rice seeds.... 相似文献